Bibcode
Kreckel, K.; Egorov, O. V.; Drory, N.; Blanc, G. A.; Méndez-Delgado, J. E.; Kabanovic, S.; Bizyaev, D.; Brownstein, J. R.; Egorova, E.; Fernández-Trincado, J. G.; García, P.; Gelfand, J. D.; Johnston, E. J.; Katkov, I.; Kollmeier, J.; Liang, F.-H.; Long, K. S.; Lugo-Aranda, A. Z.; Mejía-Narváez, A. J.; Rix, H.-W.; Roman-Lopes, A.; Román-Zúñiga, C. G.; Sattler, N.; Sanchez, S. F.; Zari, E.; Zermeño, R. de J.
Referencia bibliográfica
Astronomy and Astrophysics
Fecha de publicación:
6
2026
Revista
Número de citas
1
Número de citas referidas
0
Descripción
The so-called "Galactic center lobe" (GCL) is an extended (~1°) radio continuum feature situated above the Galactic plane, the nature and location of which have been subject to varying claims in the literature. Using new optical integral field spectroscopic observations from the SDSS-V Local Volume Mapper, we confirm the characterization of the GCL as a foreground photoionized H II region, not associated with the Galactic center. We present a new analysis of the ionized gas morphology, line ratio diagnostics, and kinematics. From our [S III]λ9532 emission line map, which suffers the least extinction, we identify ionized gas emission throughout a closed outer loop, which does not fill the GCL interior. All optical line ratio diagnostics are consistent with photoionization. By comparing the ionized gas reddening from the Balmer decrement with 3D dust maps, we directly constrain the distance to the GCL to ~2 kpc. [N II]λ6583 line kinematics show a uniform velocity structure across the GCL, further confirming that the entire bubble is one structure. The size and emission line morphology is strongly reminiscent of that seen in the nearby Barnard's Loop, providing a possible analog to explain how this outer shell may be photoionized by a more distant and off-center embedded young cluster. We suggest that the acronym GCL be repurposed to instead abbreviate the name "greatly confused loop".